If run your own root servers, it keeps your ISP from “snooping” at your otherwise encrypted https surfing and lets you cache things “locally”, not that you’ll entirely notice. You can also block known malicious domains using a tool like PiHole as your dns.
A lot of it is because this is homelab though. Your average user is fine pointing to a popular dns server like OpenDNS.
I don’t shut them down but I restart when I apply updates. Having a high uptime counter is not a badge of honor unless it’s a fancy HA system.